April, 1018] Gynandromorph in the Ilomoptera 



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margin which is characteristic of that sex. The segment in 

 this case is much shorter than the typical female, but resembles 

 it very much, while it bears no resemblance whatsoever to the 

 last ventral segment or the valve of the male. The male valve 

 in fact seems to be entirely missing and replaced by this female 

 segment. The plates, however, are well developed and typical 

 of the male* of the species. Although slightly larger in size, 

 the shape, structure and position are the same and the outer 

 margins are similarly armed with spines. 



The pygofers resemble the male of unicolor more than the 

 female structures. The opening with keeled sides at the post- 

 erior end resembles- very closely the male, but the pygofers are 

 not so strongly inflated at the middle. There is no trace, 

 however, of an ovipositor which would be a conspicuous part 

 of the genitalia in case it were a female and should extend from 

 the base to the tip of the pygofers. 



In the specimen in question a segment is found to lie just 

 beneath the last ventral segment, and the edge of which 

 protrudes slightly at the posterior end. This structure I am 

 not able to homologize with a similar one in the typical geni- 

 talia of either sex; but it is the only one not accounted for, 

 and which does not resemble in a very marked way some part 

 of one of the other specimens. 



From this comparison it is seen that there is an entire absence 

 of male structures anteriorly, replaced apparently by typical 

 female structures and a condition just the reverse of this for the 

 posterior portion, so apparently is a good example of the anterior- 

 posterior type of this phenomenon. This is not commonly 

 seen and since it occurs in the Homoptera for which group it has 

 never been reported, perhaps deserves mention here. 



